 /*******************************************************************************
  * Copyright (c) 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.resources.mapping;

 import org.eclipse.core.internal.utils.Policy;
 import org.eclipse.core.resources.*;
 import org.eclipse.core.resources.mapping.IResourceChangeDescriptionFactory;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;

 /**
  * Factory for creating a resource delta that describes a proposed change.
  */
 public class ResourceChangeDescriptionFactory implements IResourceChangeDescriptionFactory {

     private ProposedResourceDelta root = new ProposedResourceDelta(ResourcesPlugin.getWorkspace().getRoot());

     /**
      * Creates and a delta representing a deleted resource, and adds it to the provided
      * parent delta.
      * @param parentDelta The parent of the deletion delta to create
      * @param resource The deleted resource to create a delta for
      */
     private ProposedResourceDelta buildDeleteDelta(ProposedResourceDelta parentDelta, IResource resource) {
         //start with the existing delta for this resource, if any, to preserve other flags
 ProposedResourceDelta delta = parentDelta.getChild(resource.getName());
         if (delta == null) {
             delta = new ProposedResourceDelta(resource);
             parentDelta.add(delta);
         }
         delta.setKind(IResourceDelta.REMOVED);
         if (resource.getType() == IResource.FILE)
             return delta;
         //recurse to build deletion deltas for children
 try {
             IResource[] members = ((IContainer) resource).members();
             int childCount = members.length;
             if (childCount > 0) {
                 ProposedResourceDelta[] childDeltas = new ProposedResourceDelta[childCount];
                 for (int i = 0; i < childCount; i++)
                     childDeltas[i] = buildDeleteDelta(delta, members[i]);
             }
         } catch (CoreException e) {
             //don't need to create deletion deltas for children of inaccessible resources
 }
         return delta;
     }

     /* (non-Javadoc)
      * @see org.eclipse.core.resources.mapping.IProposedResourceDeltaFactory#change(org.eclipse.core.resources.IFile)
      */
     public void change(IFile file) {
         ProposedResourceDelta delta = getDelta(file);
         if (delta.getKind() == 0)
             delta.setKind(IResourceDelta.CHANGED);
         //the CONTENT flag only applies to the changed and moved from cases
 if (delta.getKind() == IResourceDelta.CHANGED
                 || (delta.getFlags() & IResourceDelta.MOVED_FROM) != 0
                 || (delta.getFlags() & IResourceDelta.COPIED_FROM) != 0)
             delta.addFlags(IResourceDelta.CONTENT);
     }

     /* (non-Javadoc)
      * @see org.eclipse.core.resources.mapping.IProposedResourceDeltaFactory#close(org.eclipse.core.resources.IProject)
      */
     public void close(IProject project) {
         delete(project);
         ProposedResourceDelta delta = getDelta(project);
         delta.addFlags(IResourceDelta.OPEN);
     }

     /* (non-Javadoc)
      * @see org.eclipse.core.resources.mapping.IProposedResourceDeltaFactory#copy(org.eclipse.core.resources.IResource, org.eclipse.core.runtime.IPath)
      */
     public void copy(IResource resource, IPath destination) {
         moveOrCopyDeep(resource, destination, false /* copy */);
     }

     /* (non-Javadoc)
      * @see org.eclipse.core.resources.mapping.IResourceChangeDescriptionFactory#create(org.eclipse.core.resources.IResource)
      */
     public void create(IResource resource) {
         getDelta(resource).setKind(IResourceDelta.ADDED);
     }

     /* (non-Javadoc)
      * @see org.eclipse.core.resources.mapping.IProposedResourceDeltaFactory#delete(org.eclipse.core.resources.IResource)
      */
     public void delete(IResource resource) {
         if (resource.getType() == IResource.ROOT) {
             //the root itself cannot be deleted, so create deletions for each project
 IProject[] projects = ((IWorkspaceRoot)resource).getProjects();
             for (int i = 0; i < projects.length; i++)
                 buildDeleteDelta(root, projects[i]);
         } else {
             buildDeleteDelta(getDelta(resource.getParent()), resource);
         }
     }

     private void fail(CoreException e) {
         Policy.log(e.getStatus().getSeverity(), "An internal error occurred while accumulating a change description.", e); //$NON-NLS-1$
 }

     /* (non-Javadoc)
      * @see org.eclipse.core.resources.mapping.IProposedResourceDeltaFactory#getDelta()
      */
     public IResourceDelta getDelta() {
         return root;
     }

     ProposedResourceDelta getDelta(IResource resource) {
         ProposedResourceDelta delta = (ProposedResourceDelta) root.findMember(resource.getFullPath());
         if (delta != null) {
             return delta;
         }
         ProposedResourceDelta parent = getDelta(resource.getParent());
         delta = new ProposedResourceDelta(resource);
         parent.add(delta);
         return delta;
     }

     /*
      * Return the resource at the destination path that corresponds to the source resource
      * @param source the source resource
      * @param sourcePrefix the path of the root of the move or copy
      * @param destinationPrefix the path of the destination the root was copied to
      * @return the destination resource
      */
     protected IResource getDestinationResource(IResource source, IPath sourcePrefix, IPath destinationPrefix) {
         IPath relativePath = source.getFullPath().removeFirstSegments(sourcePrefix.segmentCount());
         IPath destinationPath = destinationPrefix.append(relativePath);
         IResource destination;
         IWorkspaceRoot wsRoot = ResourcesPlugin.getWorkspace().getRoot();
         switch (source.getType()) {
             case IResource.FILE :
                 destination = wsRoot.getFile(destinationPath);
                 break;
             case IResource.FOLDER :
                 destination = wsRoot.getFolder(destinationPath);
                 break;
             case IResource.PROJECT :
                 destination = wsRoot.getProject(destinationPath.segment(0));
                 break;
             default :
                 // Shouldn't happen
 destination = null;
         }
         return destination;
     }

     /* (non-Javadoc)
      * @see org.eclipse.core.resources.mapping.IProposedResourceDeltaFactory#move(org.eclipse.core.resources.IResource, org.eclipse.core.runtime.IPath)
      */
     public void move(IResource resource, IPath destination) {
         moveOrCopyDeep(resource, destination, true /* move */);
     }

     /**
      * Builds the delta representing a single resource being moved or copied.
      *
      * @param resource The resource being moved
      * @param sourcePrefix The root of the sub-tree being moved
      * @param destinationPrefix The root of the destination sub-tree
      * @param move <code>true</code> for a move, <code>false</code> for a copy
      * @return Whether to move or copy the child
      */
     boolean moveOrCopy(IResource resource, final IPath sourcePrefix, final IPath destinationPrefix, final boolean move) {
         ProposedResourceDelta sourceDelta = getDelta(resource);
         if (sourceDelta.getKind() == IResourceDelta.REMOVED) {
             // There is already a removed delta here so there
 // is nothing to move/copy
 return false;
         }
         IResource destinationResource = getDestinationResource(resource, sourcePrefix, destinationPrefix);
         ProposedResourceDelta destinationDelta = getDelta(destinationResource);
         if ((destinationDelta.getKind() & (IResourceDelta.ADDED | IResourceDelta.CHANGED)) > 0) {
             // There is already a resource at the destination
 // TODO: What do we do
 return false;
         }
         // First, create the delta for the source
 IPath fromPath = resource.getFullPath();
         boolean wasAdded = false;
         final int sourceFlags = sourceDelta.getFlags();
         if (move) {
             // We transfer the source flags to the destination
 if (sourceDelta.getKind() == IResourceDelta.ADDED) {
                 if ((sourceFlags & IResourceDelta.MOVED_FROM) != 0) {
                     // The resource was moved from somewhere else so
 // we need to transfer the path to the new location
 fromPath = sourceDelta.getMovedFromPath();
                     sourceDelta.setMovedFromPath(null);
                 }
                 // The source was added and then moved so we'll
 // make it an add at the destination
 sourceDelta.setKind(0);
                 wasAdded = true;
             } else {
                 // We reset the status to be a remove/move_to
 sourceDelta.setKind(IResourceDelta.REMOVED);
                 sourceDelta.setFlags(IResourceDelta.MOVED_TO);
                 sourceDelta.setMovedToPath(destinationPrefix.append(fromPath.removeFirstSegments(sourcePrefix.segmentCount())));
             }
         }
         // Next, create the delta for the destination
 if (destinationDelta.getKind() == IResourceDelta.REMOVED) {
             // The destination was removed and is being re-added
 destinationDelta.setKind(IResourceDelta.CHANGED);
             destinationDelta.addFlags(IResourceDelta.REPLACED);
         } else {
             destinationDelta.setKind(IResourceDelta.ADDED);
         }
         if (!wasAdded || !fromPath.equals(resource.getFullPath())) {
             // The source wasn't added so it is a move/copy
 destinationDelta.addFlags(move ? IResourceDelta.MOVED_FROM : IResourceDelta.COPIED_FROM);
             destinationDelta.setMovedFromPath(fromPath);
             // Apply the source flags
 if (move)
                 destinationDelta.addFlags(sourceFlags);
         }

         return true;
     }

     /**
      * Helper method that generate a move or copy delta for a sub-tree
      * of resources being moved or copied.
      */
     private void moveOrCopyDeep(IResource resource, IPath destination, final boolean move) {
         final IPath sourcePrefix = resource.getFullPath();
         final IPath destinationPrefix = destination;
         try {
             //build delta for the entire sub-tree if available
 if (resource.isAccessible()) {
                 resource.accept(new IResourceVisitor() {
                     public boolean visit(IResource child) {
                         return moveOrCopy(child, sourcePrefix, destinationPrefix, move);
                     }
                 });
             } else {
                 //just build a delta for the single resource
 moveOrCopy(resource, sourcePrefix, destination, move);
             }
         } catch (CoreException e) {
             fail(e);
         }
     }
 }

